Antibodies have received much attention as a medicine because of their high stability in blood and low antigenicity. Of these are bispecific antibodies that can simultaneously recognize two types of antigens. Bispecific antibodies have been proposed for some time; however, only antibodies that simply connect two types of antigens, such as those for retargeting NK cells, macrophages, and T cells (see Non-Patent Document 7), have been reported. For example, MDX-210, which is currently under clinical study, is a bispecific antibody that merely retargets FcγRI-expressing monocytes and such to HER-2/neu-expressing cancer cells. Thus, there is no example so far that utilizes a bispecific antibody as an alternative means to functionally substitute for the cofactor which enhances enzymatic reaction.
Examples of cofactors are tissue factor (TF), blood coagulation factor V (F.V), activated blood coagulation factor V (F.Va), blood coagulation factor VIII (F.VIII), activated blood coagulation factor VIII (F.VIIIa), thrombomodulin (TM), protein S (PS), protein Z (PZ), heparin, complement C4b, complement regulatory factor H, membrane cofactor protein (MCP), and complement receptor 1 (CR1).
Of these, F.VIIIIF.VIIIa is a cofactor required for sufficient activity expression of activated blood coagulation factor IX (F.IXa). Scheiflinger F. et al. discovered that a certain anti-F.IXDF.IXa antibody acts to promote the activation of blood coagulation factor X (F.X) by F.IXa in a chromogenic assay (Patent Document 1). However, in an assay that examines the ability for coagulation recovery in F.VIII-deficient plasma, the coagulation recovery ability was observed only when F.IXa was added exogenously, but not if this antibody was used alone.
F.VIIIa has been known to interact with not only F.IXa but also with F.X (see Non-Patent Documents 5 and 6). In this respect, the antibody of Scheiflinger F. et al. cannot be said to sufficiently substitute for the function of F.VIII/F.VIIIa, and its activity also seems to be insufficient.
Through dedicated research, the present inventors succeeded in producing bispecific antibodies that functionally substitute for the cofactors which enhance enzymatic activity, and thereby completed this invention.    [Patent Document 1] WO 01/19992    [Patent Document 2] U.S. Pat. No. 4,474,893    [Patent Document 3] EP 404,097    [Patent Document 4] WO 93/11161    [Patent Document 5] Japanese Patent Application No: 2002-112369    [Patent Document 6] Japanese Patent Application No: 2003-012648    [Patent Document 7] Japanese Patent Application Kokai Publication No. (JP-A) H5-304992 (unexamined, published Japanese patent application)    [Patent Document 8] JP-A H2-145187    [Patent Document 9] JP-A H5-213775    [Patent Document 10] JP-A H110-165184    [Patent Document 11] JP-A H111-71288    [Patent Document 12] JP-A 2002-518041    [Patent Document 13] JP-A H 11-506310    [Patent Document 14] JP-A H5-199894    [Patent Document 15] JP-A H110-511085    [Patent Document 16] JP-A H5-184383    [Non-Patent Document 1] Nilsson I M et al., “J. Intern. Med.” 1992, Vol.235, p.25-32    [Non-Patent Document 2] Lofqvist T et al,. “J. Intern. Med” 1997, Vol.241, p.395-400 (the “o” of Lofqvist is written with an umlaut)    [Non-Patent Document 3] 24th Meeting of The Japanese Society on Thrombosis and Hematosis, Special Committee on Examining Hemophilia Standardization, Mini-symposium, 2001, http://wwwjsth.org    [Non-Patent Document 4] Medical Bulletin #193 1994    [Non-Patent Document 5] Mertens K et al., “Thromb. Haemost.” 1999, Vol.82, p.209-217    [Non-Patent Document 6] Lapan K A et al., “Thromb. Haemost.” 1998, Vol.80, p.418-422    [Non-Patent Document 7] Segal D M et al., “Journal of Immunological Methods” 2001, Vol.248, p.1-6    [Non-Patent Document 8] Bos R and Nieuwenhuitzen W, “Hybridoma” 1992, Vol.11, No. 1, p.41-51    [Non-Patent Document 9] Brennan M et al., “Science” 1985, Vol.229, No.1708, p.81-3    [Non-Patent Document 10] Karpovsky B et al., “J. Exp. Med.” 1984, Vol.160, No.6, p.1686-701    [Non-Patent Document 11] Suresh M R et al., “Methods Enzymol.” 1986, Vol.121, p. 210-28    [Non-Patent Document 12] Massimo Y S et al., “J. Immunol. Methods” 1997, Vol.201, p.57-66    [Non-Patent Document 13] Brennan M et al., “Science” 1985, Vol.229, p.81    [Non-Patent Document 14] Shalaby M R et al., “J. Exp. Med.” 1992, Vol.175, p.217-25    [Non-Patent Document 15] Holliner P et al., “Proc. Natl. Acad. Sci. USA” 1993, Vol.90, p. 6444-8    [Non-Patent Document 16] Ridgway J B et al., “Protein Eng.” 1996, Vol.9, p. 617-21    [Non-Patent Document 17] Hammerling U et al., “J. Exp. Med.” 1968, Vol.128, p.1461-73    [Non-Patent Document 18] Kurokawa T et al., “Bio/Technology” 1989, Vol.7, p.1163    [Non-Patent Document 19] Link B K et al., “Blood” 1993, Vol.81, p.3343    [Non-Patent Document 20] Nitta T et al., “Lancet” 1990, Vol.335, p.368-71    [Non-Patent Document 21 ] deLeij L et al., “Foundation Nationale de Transfusion Sanguine, Les Ulis France” 1990, p.249-53    [Non-Patent Document 22] Le Doussal J M et al., “J. Nucl. Med.” 1993, Vol.34, p.1662-71    [Non-Patent Document 23] Stickney D R et al., “Cancer Res.” 1991, Vol.51, p.6650-5    [Non-Patent Document 24] Weiner L M et al., “Cancer Res.” 1993, Vol.53, p.94-100    [Non-Patent Document 25] Kroesen B J et al., “Br. J. Cancer” 1994, Vol.70, p.652-61    [Non-Patent Document 26] Weiner G J et al., “J. Immunol.” 1994, Vol.152, p.2385    [Non-Patent Document 27] Suresh M R et al., “Proc. Natl. Acad. Sci. USA” 1986, Vol.83, p.7989-93    [Non-Patent Document 28] Milstein C and Cuello A C, “Nature” 1983, Vol.305, p.537    [Non-Patent Document 29] Xiang J et al., “Mol. Immunol.” 1990, Vol.27, p.809    [Non-Patent Document 30] Bebbington C R et al., “Bio/Technology” 1992, Vol.10, p.169    [Non-Patent Document 31] Huse W D et al., “Science” 1989, Vol. 246, p.1275    [Non-Patent Document 32] McCafferty J et al., “Nature” 1990, Vol.348, p.552    [Non-Patent Document 33] Kang A S et al., “Proc. Natl. Acad. Sci. USA” 1991, Vol.88, p.4363